Anticipating and tracking orientation-specific information for moving objects in 4- to 6-month-old infants

Purpose. The purpose of this study is to examine the early capacity to track invisible spatial transformations. In particular, we tested at what age infants could anticipate an object orientation following a partly occluded transformation. Method. In three experiments, 4- and 6-month-old infants were tested in a looking paradigm to assess their reaction to surreptitious changes in an object's orientation. The same procedure was used in all three experiments except the object and the size of the occluder were varied. Infants were familiarized to an object disappearing behind an occluder following either a translation (vertical fall), or a rotational motion (180° arc). The endpoint of both motions was occluded by a screen so that the final orientation of the object was not visible. In the translation condition, the object was presented at the top of the display and moved at a constant velocity 80 cm down a vertical track to the bottom of the display. In the rotation condition, the object moved at a constant velocity in a 180° arc from 12 o'clock to 6 o'clock. Following familiarization, infants were shown six test trials. In the test trials, infants saw the object disappearing behind the occluder, then the occluder was removed. On alternating test trials, infants were presented with the object in the appropriate orientation outcome (possible orientation), or rotated by 180° (impossible orientation). Looking time at the revealed object was measured. Results. In the first experiment, 4- and 6-monih-old infants looked significantly longer at the impossible compared to the possible orientation outcome. In a second and third experiment, 6- but not 4-month-olds looked significantly longer at the impossible compared to the possible orientation outcome in a condition where the object afforded fewer orientation-specific cues (Exp. 2), and in a condition where a larger portion of the transformation was occluded (Exp. 3). Conclusions. These findings are interpreted as evidence of an early capacity to detect orientation-specific information. The results suggest that the ability to generate dynamic mental imagery is expressed by 4 months and develops rapidly.